Re-irradiation plus regional hyperthermia for recurrent non-small cell lung cancer: a potential modality for inducing long-term survival in selected patients.

PURPOSE The purpose of this study was to assess the toxicity and efficacy of re-irradiation plus regional hyperthermia for recurrent NSCLC and to identify the predictors of long-term survival. METHODS AND MATERIALS A total of 33 patients with recurrent NSCLC treated with re-irradiation plus regional hyperthermia were retrospectively analyzed. The median total dose of initial radiotherapy and re-irradiation were 70 Gy and 50 Gy, respectively. A median of 5 hyperthermia treatments using an 8-MHz radiofrequency-capacitive device were applied during re-irradiation in all patients. RESULTS Toxicity of Grade 3 was seen in 3 (9%) patients, and no Grade 4 or 5 toxicity was observed. The median overall survival, local control, and disease progression-free survival times after re-irradiation were 18.1, 12.1, and 6.7 months, respectively. Eight patients achieved a long-term survival (more than 3 years after re-irradiation), and 4 of them underwent a third round of irradiation for re-recurrent tumors. Univariate analyses showed that a smaller tumor size (<4 cm) and the absence of distant metastases were significant predictors for a better overall survival. The absence of distant metastases was also found to be a significant predictor for better disease progression-free survival in the univariate analyses. In the subset analyses of 23 patients treated with hyperthermia using electrodes of 30 cm in diameter, the use of a higher radiofrequency-output power tended to be associated with a better prognosis in terms of the local control rate. CONCLUSIONS Re-irradiation plus regional hyperthermia for recurrent NSCLC appears feasible, with acceptable toxicity, and may be a promising treatment that can result in the long-term survival of patients without distant metastasis and larger recurrent tumors.